The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 9eee5330656bf92f51cb1f09b2dc9f8cf975b3d1 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024070120-undergo-stipulate-9aae@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
9eee5330656b ("PCI/MSI: Fix UAF in msi_capability_init") b12d0bec385b ("PCI/MSI: Move pci_disable_msi() to api.c") c93fd5266cff ("PCI/MSI: Move mask and unmask helpers to msi.h") a474d3fbe287 ("PCI/MSI: Get rid of PCI_MSI_IRQ_DOMAIN")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 9eee5330656bf92f51cb1f09b2dc9f8cf975b3d1 Mon Sep 17 00:00:00 2001 From: Mostafa Saleh smostafa@google.com Date: Mon, 24 Jun 2024 20:37:28 +0000 Subject: [PATCH] PCI/MSI: Fix UAF in msi_capability_init
KFENCE reports the following UAF:
BUG: KFENCE: use-after-free read in __pci_enable_msi_range+0x2c0/0x488
Use-after-free read at 0x0000000024629571 (in kfence-#12): __pci_enable_msi_range+0x2c0/0x488 pci_alloc_irq_vectors_affinity+0xec/0x14c pci_alloc_irq_vectors+0x18/0x28
kfence-#12: 0x0000000008614900-0x00000000e06c228d, size=104, cache=kmalloc-128
allocated by task 81 on cpu 7 at 10.808142s: __kmem_cache_alloc_node+0x1f0/0x2bc kmalloc_trace+0x44/0x138 msi_alloc_desc+0x3c/0x9c msi_domain_insert_msi_desc+0x30/0x78 msi_setup_msi_desc+0x13c/0x184 __pci_enable_msi_range+0x258/0x488 pci_alloc_irq_vectors_affinity+0xec/0x14c pci_alloc_irq_vectors+0x18/0x28
freed by task 81 on cpu 7 at 10.811436s: msi_domain_free_descs+0xd4/0x10c msi_domain_free_locked.part.0+0xc0/0x1d8 msi_domain_alloc_irqs_all_locked+0xb4/0xbc pci_msi_setup_msi_irqs+0x30/0x4c __pci_enable_msi_range+0x2a8/0x488 pci_alloc_irq_vectors_affinity+0xec/0x14c pci_alloc_irq_vectors+0x18/0x28
Descriptor allocation done in: __pci_enable_msi_range msi_capability_init msi_setup_msi_desc msi_insert_msi_desc msi_domain_insert_msi_desc msi_alloc_desc ...
Freed in case of failure in __msi_domain_alloc_locked() __pci_enable_msi_range msi_capability_init pci_msi_setup_msi_irqs msi_domain_alloc_irqs_all_locked msi_domain_alloc_locked __msi_domain_alloc_locked => fails msi_domain_free_locked ...
That failure propagates back to pci_msi_setup_msi_irqs() in msi_capability_init() which accesses the descriptor for unmasking in the error exit path.
Cure it by copying the descriptor and using the copy for the error exit path unmask operation.
[ tglx: Massaged change log ]
Fixes: bf6e054e0e3f ("genirq/msi: Provide msi_device_populate/destroy_sysfs()") Suggested-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Mostafa Saleh smostafa@google.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Bjorn Heelgas bhelgaas@google.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240624203729.1094506-1-smostafa@google.com
diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c index c5625dd9bf49..3a45879d85db 100644 --- a/drivers/pci/msi/msi.c +++ b/drivers/pci/msi/msi.c @@ -352,7 +352,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec, struct irq_affinity *affd) { struct irq_affinity_desc *masks = NULL; - struct msi_desc *entry; + struct msi_desc *entry, desc; int ret;
/* Reject multi-MSI early on irq domain enabled architectures */ @@ -377,6 +377,12 @@ static int msi_capability_init(struct pci_dev *dev, int nvec, /* All MSIs are unmasked by default; mask them all */ entry = msi_first_desc(&dev->dev, MSI_DESC_ALL); pci_msi_mask(entry, msi_multi_mask(entry)); + /* + * Copy the MSI descriptor for the error path because + * pci_msi_setup_msi_irqs() will free it for the hierarchical + * interrupt domain case. + */ + memcpy(&desc, entry, sizeof(desc));
/* Configure MSI capability structure */ ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI); @@ -396,7 +402,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec, goto unlock;
err: - pci_msi_unmask(entry, msi_multi_mask(entry)); + pci_msi_unmask(&desc, msi_multi_mask(&desc)); pci_free_msi_irqs(dev); fail: dev->msi_enabled = 0;